1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/debugfs.h> 25 #include <linux/smp_lock.h> 26 #include <linux/time.h> 27 #include <linux/uaccess.h> 28 29 #include <trace/events/block.h> 30 31 #include "trace_output.h" 32 33 #ifdef CONFIG_BLK_DEV_IO_TRACE 34 35 static unsigned int blktrace_seq __read_mostly = 1; 36 37 static struct trace_array *blk_tr; 38 static bool blk_tracer_enabled __read_mostly; 39 40 /* Select an alternative, minimalistic output than the original one */ 41 #define TRACE_BLK_OPT_CLASSIC 0x1 42 43 static struct tracer_opt blk_tracer_opts[] = { 44 /* Default disable the minimalistic output */ 45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 46 { } 47 }; 48 49 static struct tracer_flags blk_tracer_flags = { 50 .val = 0, 51 .opts = blk_tracer_opts, 52 }; 53 54 /* Global reference count of probes */ 55 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 56 57 static void blk_register_tracepoints(void); 58 static void blk_unregister_tracepoints(void); 59 60 /* 61 * Send out a notify message. 62 */ 63 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 64 const void *data, size_t len) 65 { 66 struct blk_io_trace *t; 67 struct ring_buffer_event *event = NULL; 68 int pc = 0; 69 int cpu = smp_processor_id(); 70 bool blk_tracer = blk_tracer_enabled; 71 72 if (blk_tracer) { 73 pc = preempt_count(); 74 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK, 75 sizeof(*t) + len, 76 0, pc); 77 if (!event) 78 return; 79 t = ring_buffer_event_data(event); 80 goto record_it; 81 } 82 83 if (!bt->rchan) 84 return; 85 86 t = relay_reserve(bt->rchan, sizeof(*t) + len); 87 if (t) { 88 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 89 t->time = ktime_to_ns(ktime_get()); 90 record_it: 91 t->device = bt->dev; 92 t->action = action; 93 t->pid = pid; 94 t->cpu = cpu; 95 t->pdu_len = len; 96 memcpy((void *) t + sizeof(*t), data, len); 97 98 if (blk_tracer) 99 trace_buffer_unlock_commit(blk_tr, event, 0, pc); 100 } 101 } 102 103 /* 104 * Send out a notify for this process, if we haven't done so since a trace 105 * started 106 */ 107 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) 108 { 109 tsk->btrace_seq = blktrace_seq; 110 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); 111 } 112 113 static void trace_note_time(struct blk_trace *bt) 114 { 115 struct timespec now; 116 unsigned long flags; 117 u32 words[2]; 118 119 getnstimeofday(&now); 120 words[0] = now.tv_sec; 121 words[1] = now.tv_nsec; 122 123 local_irq_save(flags); 124 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 125 local_irq_restore(flags); 126 } 127 128 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 129 { 130 int n; 131 va_list args; 132 unsigned long flags; 133 char *buf; 134 135 if (unlikely(bt->trace_state != Blktrace_running && 136 !blk_tracer_enabled)) 137 return; 138 139 local_irq_save(flags); 140 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 141 va_start(args, fmt); 142 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 143 va_end(args); 144 145 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 146 local_irq_restore(flags); 147 } 148 EXPORT_SYMBOL_GPL(__trace_note_message); 149 150 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 151 pid_t pid) 152 { 153 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 154 return 1; 155 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 156 return 1; 157 if (bt->pid && pid != bt->pid) 158 return 1; 159 160 return 0; 161 } 162 163 /* 164 * Data direction bit lookup 165 */ 166 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 167 BLK_TC_ACT(BLK_TC_WRITE) }; 168 169 /* The ilog2() calls fall out because they're constant */ 170 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \ 171 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name)) 172 173 /* 174 * The worker for the various blk_add_trace*() types. Fills out a 175 * blk_io_trace structure and places it in a per-cpu subbuffer. 176 */ 177 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 178 int rw, u32 what, int error, int pdu_len, void *pdu_data) 179 { 180 struct task_struct *tsk = current; 181 struct ring_buffer_event *event = NULL; 182 struct blk_io_trace *t; 183 unsigned long flags = 0; 184 unsigned long *sequence; 185 pid_t pid; 186 int cpu, pc = 0; 187 bool blk_tracer = blk_tracer_enabled; 188 189 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 190 return; 191 192 what |= ddir_act[rw & WRITE]; 193 what |= MASK_TC_BIT(rw, BARRIER); 194 what |= MASK_TC_BIT(rw, SYNCIO); 195 what |= MASK_TC_BIT(rw, AHEAD); 196 what |= MASK_TC_BIT(rw, META); 197 what |= MASK_TC_BIT(rw, DISCARD); 198 199 pid = tsk->pid; 200 if (act_log_check(bt, what, sector, pid)) 201 return; 202 cpu = raw_smp_processor_id(); 203 204 if (blk_tracer) { 205 tracing_record_cmdline(current); 206 207 pc = preempt_count(); 208 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK, 209 sizeof(*t) + pdu_len, 210 0, pc); 211 if (!event) 212 return; 213 t = ring_buffer_event_data(event); 214 goto record_it; 215 } 216 217 /* 218 * A word about the locking here - we disable interrupts to reserve 219 * some space in the relay per-cpu buffer, to prevent an irq 220 * from coming in and stepping on our toes. 221 */ 222 local_irq_save(flags); 223 224 if (unlikely(tsk->btrace_seq != blktrace_seq)) 225 trace_note_tsk(bt, tsk); 226 227 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 228 if (t) { 229 sequence = per_cpu_ptr(bt->sequence, cpu); 230 231 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 232 t->sequence = ++(*sequence); 233 t->time = ktime_to_ns(ktime_get()); 234 record_it: 235 /* 236 * These two are not needed in ftrace as they are in the 237 * generic trace_entry, filled by tracing_generic_entry_update, 238 * but for the trace_event->bin() synthesizer benefit we do it 239 * here too. 240 */ 241 t->cpu = cpu; 242 t->pid = pid; 243 244 t->sector = sector; 245 t->bytes = bytes; 246 t->action = what; 247 t->device = bt->dev; 248 t->error = error; 249 t->pdu_len = pdu_len; 250 251 if (pdu_len) 252 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 253 254 if (blk_tracer) { 255 trace_buffer_unlock_commit(blk_tr, event, 0, pc); 256 return; 257 } 258 } 259 260 local_irq_restore(flags); 261 } 262 263 static struct dentry *blk_tree_root; 264 static DEFINE_MUTEX(blk_tree_mutex); 265 266 static void blk_trace_free(struct blk_trace *bt) 267 { 268 debugfs_remove(bt->msg_file); 269 debugfs_remove(bt->dropped_file); 270 debugfs_remove(bt->dir); 271 relay_close(bt->rchan); 272 free_percpu(bt->sequence); 273 free_percpu(bt->msg_data); 274 kfree(bt); 275 } 276 277 static void blk_trace_cleanup(struct blk_trace *bt) 278 { 279 blk_trace_free(bt); 280 if (atomic_dec_and_test(&blk_probes_ref)) 281 blk_unregister_tracepoints(); 282 } 283 284 int blk_trace_remove(struct request_queue *q) 285 { 286 struct blk_trace *bt; 287 288 bt = xchg(&q->blk_trace, NULL); 289 if (!bt) 290 return -EINVAL; 291 292 if (bt->trace_state != Blktrace_running) 293 blk_trace_cleanup(bt); 294 295 return 0; 296 } 297 EXPORT_SYMBOL_GPL(blk_trace_remove); 298 299 static int blk_dropped_open(struct inode *inode, struct file *filp) 300 { 301 filp->private_data = inode->i_private; 302 303 return 0; 304 } 305 306 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 307 size_t count, loff_t *ppos) 308 { 309 struct blk_trace *bt = filp->private_data; 310 char buf[16]; 311 312 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 313 314 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 315 } 316 317 static const struct file_operations blk_dropped_fops = { 318 .owner = THIS_MODULE, 319 .open = blk_dropped_open, 320 .read = blk_dropped_read, 321 }; 322 323 static int blk_msg_open(struct inode *inode, struct file *filp) 324 { 325 filp->private_data = inode->i_private; 326 327 return 0; 328 } 329 330 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 331 size_t count, loff_t *ppos) 332 { 333 char *msg; 334 struct blk_trace *bt; 335 336 if (count >= BLK_TN_MAX_MSG) 337 return -EINVAL; 338 339 msg = kmalloc(count + 1, GFP_KERNEL); 340 if (msg == NULL) 341 return -ENOMEM; 342 343 if (copy_from_user(msg, buffer, count)) { 344 kfree(msg); 345 return -EFAULT; 346 } 347 348 msg[count] = '\0'; 349 bt = filp->private_data; 350 __trace_note_message(bt, "%s", msg); 351 kfree(msg); 352 353 return count; 354 } 355 356 static const struct file_operations blk_msg_fops = { 357 .owner = THIS_MODULE, 358 .open = blk_msg_open, 359 .write = blk_msg_write, 360 }; 361 362 /* 363 * Keep track of how many times we encountered a full subbuffer, to aid 364 * the user space app in telling how many lost events there were. 365 */ 366 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 367 void *prev_subbuf, size_t prev_padding) 368 { 369 struct blk_trace *bt; 370 371 if (!relay_buf_full(buf)) 372 return 1; 373 374 bt = buf->chan->private_data; 375 atomic_inc(&bt->dropped); 376 return 0; 377 } 378 379 static int blk_remove_buf_file_callback(struct dentry *dentry) 380 { 381 struct dentry *parent = dentry->d_parent; 382 debugfs_remove(dentry); 383 384 /* 385 * this will fail for all but the last file, but that is ok. what we 386 * care about is the top level buts->name directory going away, when 387 * the last trace file is gone. Then we don't have to rmdir() that 388 * manually on trace stop, so it nicely solves the issue with 389 * force killing of running traces. 390 */ 391 392 debugfs_remove(parent); 393 return 0; 394 } 395 396 static struct dentry *blk_create_buf_file_callback(const char *filename, 397 struct dentry *parent, 398 int mode, 399 struct rchan_buf *buf, 400 int *is_global) 401 { 402 return debugfs_create_file(filename, mode, parent, buf, 403 &relay_file_operations); 404 } 405 406 static struct rchan_callbacks blk_relay_callbacks = { 407 .subbuf_start = blk_subbuf_start_callback, 408 .create_buf_file = blk_create_buf_file_callback, 409 .remove_buf_file = blk_remove_buf_file_callback, 410 }; 411 412 static void blk_trace_setup_lba(struct blk_trace *bt, 413 struct block_device *bdev) 414 { 415 struct hd_struct *part = NULL; 416 417 if (bdev) 418 part = bdev->bd_part; 419 420 if (part) { 421 bt->start_lba = part->start_sect; 422 bt->end_lba = part->start_sect + part->nr_sects; 423 } else { 424 bt->start_lba = 0; 425 bt->end_lba = -1ULL; 426 } 427 } 428 429 /* 430 * Setup everything required to start tracing 431 */ 432 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 433 struct block_device *bdev, 434 struct blk_user_trace_setup *buts) 435 { 436 struct blk_trace *old_bt, *bt = NULL; 437 struct dentry *dir = NULL; 438 int ret, i; 439 440 if (!buts->buf_size || !buts->buf_nr) 441 return -EINVAL; 442 443 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 444 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 445 446 /* 447 * some device names have larger paths - convert the slashes 448 * to underscores for this to work as expected 449 */ 450 for (i = 0; i < strlen(buts->name); i++) 451 if (buts->name[i] == '/') 452 buts->name[i] = '_'; 453 454 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 455 if (!bt) 456 return -ENOMEM; 457 458 ret = -ENOMEM; 459 bt->sequence = alloc_percpu(unsigned long); 460 if (!bt->sequence) 461 goto err; 462 463 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 464 if (!bt->msg_data) 465 goto err; 466 467 ret = -ENOENT; 468 469 mutex_lock(&blk_tree_mutex); 470 if (!blk_tree_root) { 471 blk_tree_root = debugfs_create_dir("block", NULL); 472 if (!blk_tree_root) { 473 mutex_unlock(&blk_tree_mutex); 474 goto err; 475 } 476 } 477 mutex_unlock(&blk_tree_mutex); 478 479 dir = debugfs_create_dir(buts->name, blk_tree_root); 480 481 if (!dir) 482 goto err; 483 484 bt->dir = dir; 485 bt->dev = dev; 486 atomic_set(&bt->dropped, 0); 487 488 ret = -EIO; 489 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 490 &blk_dropped_fops); 491 if (!bt->dropped_file) 492 goto err; 493 494 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 495 if (!bt->msg_file) 496 goto err; 497 498 bt->rchan = relay_open("trace", dir, buts->buf_size, 499 buts->buf_nr, &blk_relay_callbacks, bt); 500 if (!bt->rchan) 501 goto err; 502 503 bt->act_mask = buts->act_mask; 504 if (!bt->act_mask) 505 bt->act_mask = (u16) -1; 506 507 blk_trace_setup_lba(bt, bdev); 508 509 /* overwrite with user settings */ 510 if (buts->start_lba) 511 bt->start_lba = buts->start_lba; 512 if (buts->end_lba) 513 bt->end_lba = buts->end_lba; 514 515 bt->pid = buts->pid; 516 bt->trace_state = Blktrace_setup; 517 518 ret = -EBUSY; 519 old_bt = xchg(&q->blk_trace, bt); 520 if (old_bt) { 521 (void) xchg(&q->blk_trace, old_bt); 522 goto err; 523 } 524 525 if (atomic_inc_return(&blk_probes_ref) == 1) 526 blk_register_tracepoints(); 527 528 return 0; 529 err: 530 blk_trace_free(bt); 531 return ret; 532 } 533 534 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 535 struct block_device *bdev, 536 char __user *arg) 537 { 538 struct blk_user_trace_setup buts; 539 int ret; 540 541 ret = copy_from_user(&buts, arg, sizeof(buts)); 542 if (ret) 543 return -EFAULT; 544 545 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 546 if (ret) 547 return ret; 548 549 if (copy_to_user(arg, &buts, sizeof(buts))) 550 return -EFAULT; 551 552 return 0; 553 } 554 EXPORT_SYMBOL_GPL(blk_trace_setup); 555 556 int blk_trace_startstop(struct request_queue *q, int start) 557 { 558 int ret; 559 struct blk_trace *bt = q->blk_trace; 560 561 if (bt == NULL) 562 return -EINVAL; 563 564 /* 565 * For starting a trace, we can transition from a setup or stopped 566 * trace. For stopping a trace, the state must be running 567 */ 568 ret = -EINVAL; 569 if (start) { 570 if (bt->trace_state == Blktrace_setup || 571 bt->trace_state == Blktrace_stopped) { 572 blktrace_seq++; 573 smp_mb(); 574 bt->trace_state = Blktrace_running; 575 576 trace_note_time(bt); 577 ret = 0; 578 } 579 } else { 580 if (bt->trace_state == Blktrace_running) { 581 bt->trace_state = Blktrace_stopped; 582 relay_flush(bt->rchan); 583 ret = 0; 584 } 585 } 586 587 return ret; 588 } 589 EXPORT_SYMBOL_GPL(blk_trace_startstop); 590 591 /** 592 * blk_trace_ioctl: - handle the ioctls associated with tracing 593 * @bdev: the block device 594 * @cmd: the ioctl cmd 595 * @arg: the argument data, if any 596 * 597 **/ 598 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 599 { 600 struct request_queue *q; 601 int ret, start = 0; 602 char b[BDEVNAME_SIZE]; 603 604 q = bdev_get_queue(bdev); 605 if (!q) 606 return -ENXIO; 607 608 mutex_lock(&bdev->bd_mutex); 609 610 switch (cmd) { 611 case BLKTRACESETUP: 612 bdevname(bdev, b); 613 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 614 break; 615 case BLKTRACESTART: 616 start = 1; 617 case BLKTRACESTOP: 618 ret = blk_trace_startstop(q, start); 619 break; 620 case BLKTRACETEARDOWN: 621 ret = blk_trace_remove(q); 622 break; 623 default: 624 ret = -ENOTTY; 625 break; 626 } 627 628 mutex_unlock(&bdev->bd_mutex); 629 return ret; 630 } 631 632 /** 633 * blk_trace_shutdown: - stop and cleanup trace structures 634 * @q: the request queue associated with the device 635 * 636 **/ 637 void blk_trace_shutdown(struct request_queue *q) 638 { 639 if (q->blk_trace) { 640 blk_trace_startstop(q, 0); 641 blk_trace_remove(q); 642 } 643 } 644 645 /* 646 * blktrace probes 647 */ 648 649 /** 650 * blk_add_trace_rq - Add a trace for a request oriented action 651 * @q: queue the io is for 652 * @rq: the source request 653 * @what: the action 654 * 655 * Description: 656 * Records an action against a request. Will log the bio offset + size. 657 * 658 **/ 659 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 660 u32 what) 661 { 662 struct blk_trace *bt = q->blk_trace; 663 int rw = rq->cmd_flags & 0x03; 664 665 if (likely(!bt)) 666 return; 667 668 if (blk_discard_rq(rq)) 669 rw |= (1 << BIO_RW_DISCARD); 670 671 if (blk_pc_request(rq)) { 672 what |= BLK_TC_ACT(BLK_TC_PC); 673 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw, 674 what, rq->errors, rq->cmd_len, rq->cmd); 675 } else { 676 what |= BLK_TC_ACT(BLK_TC_FS); 677 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw, 678 what, rq->errors, 0, NULL); 679 } 680 } 681 682 static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq) 683 { 684 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 685 } 686 687 static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq) 688 { 689 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 690 } 691 692 static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq) 693 { 694 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 695 } 696 697 static void blk_add_trace_rq_requeue(struct request_queue *q, 698 struct request *rq) 699 { 700 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 701 } 702 703 static void blk_add_trace_rq_complete(struct request_queue *q, 704 struct request *rq) 705 { 706 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 707 } 708 709 /** 710 * blk_add_trace_bio - Add a trace for a bio oriented action 711 * @q: queue the io is for 712 * @bio: the source bio 713 * @what: the action 714 * 715 * Description: 716 * Records an action against a bio. Will log the bio offset + size. 717 * 718 **/ 719 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 720 u32 what) 721 { 722 struct blk_trace *bt = q->blk_trace; 723 724 if (likely(!bt)) 725 return; 726 727 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 728 !bio_flagged(bio, BIO_UPTODATE), 0, NULL); 729 } 730 731 static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio) 732 { 733 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); 734 } 735 736 static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio) 737 { 738 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); 739 } 740 741 static void blk_add_trace_bio_backmerge(struct request_queue *q, 742 struct bio *bio) 743 { 744 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); 745 } 746 747 static void blk_add_trace_bio_frontmerge(struct request_queue *q, 748 struct bio *bio) 749 { 750 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); 751 } 752 753 static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio) 754 { 755 blk_add_trace_bio(q, bio, BLK_TA_QUEUE); 756 } 757 758 static void blk_add_trace_getrq(struct request_queue *q, 759 struct bio *bio, int rw) 760 { 761 if (bio) 762 blk_add_trace_bio(q, bio, BLK_TA_GETRQ); 763 else { 764 struct blk_trace *bt = q->blk_trace; 765 766 if (bt) 767 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 768 } 769 } 770 771 772 static void blk_add_trace_sleeprq(struct request_queue *q, 773 struct bio *bio, int rw) 774 { 775 if (bio) 776 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); 777 else { 778 struct blk_trace *bt = q->blk_trace; 779 780 if (bt) 781 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 782 0, 0, NULL); 783 } 784 } 785 786 static void blk_add_trace_plug(struct request_queue *q) 787 { 788 struct blk_trace *bt = q->blk_trace; 789 790 if (bt) 791 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 792 } 793 794 static void blk_add_trace_unplug_io(struct request_queue *q) 795 { 796 struct blk_trace *bt = q->blk_trace; 797 798 if (bt) { 799 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 800 __be64 rpdu = cpu_to_be64(pdu); 801 802 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 803 sizeof(rpdu), &rpdu); 804 } 805 } 806 807 static void blk_add_trace_unplug_timer(struct request_queue *q) 808 { 809 struct blk_trace *bt = q->blk_trace; 810 811 if (bt) { 812 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 813 __be64 rpdu = cpu_to_be64(pdu); 814 815 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 816 sizeof(rpdu), &rpdu); 817 } 818 } 819 820 static void blk_add_trace_split(struct request_queue *q, struct bio *bio, 821 unsigned int pdu) 822 { 823 struct blk_trace *bt = q->blk_trace; 824 825 if (bt) { 826 __be64 rpdu = cpu_to_be64(pdu); 827 828 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 829 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 830 sizeof(rpdu), &rpdu); 831 } 832 } 833 834 /** 835 * blk_add_trace_remap - Add a trace for a remap operation 836 * @q: queue the io is for 837 * @bio: the source bio 838 * @dev: target device 839 * @from: source sector 840 * 841 * Description: 842 * Device mapper or raid target sometimes need to split a bio because 843 * it spans a stripe (or similar). Add a trace for that action. 844 * 845 **/ 846 static void blk_add_trace_remap(struct request_queue *q, struct bio *bio, 847 dev_t dev, sector_t from) 848 { 849 struct blk_trace *bt = q->blk_trace; 850 struct blk_io_trace_remap r; 851 852 if (likely(!bt)) 853 return; 854 855 r.device_from = cpu_to_be32(dev); 856 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 857 r.sector_from = cpu_to_be64(from); 858 859 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 860 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 861 sizeof(r), &r); 862 } 863 864 /** 865 * blk_add_driver_data - Add binary message with driver-specific data 866 * @q: queue the io is for 867 * @rq: io request 868 * @data: driver-specific data 869 * @len: length of driver-specific data 870 * 871 * Description: 872 * Some drivers might want to write driver-specific data per request. 873 * 874 **/ 875 void blk_add_driver_data(struct request_queue *q, 876 struct request *rq, 877 void *data, size_t len) 878 { 879 struct blk_trace *bt = q->blk_trace; 880 881 if (likely(!bt)) 882 return; 883 884 if (blk_pc_request(rq)) 885 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 886 BLK_TA_DRV_DATA, rq->errors, len, data); 887 else 888 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 889 BLK_TA_DRV_DATA, rq->errors, len, data); 890 } 891 EXPORT_SYMBOL_GPL(blk_add_driver_data); 892 893 static void blk_register_tracepoints(void) 894 { 895 int ret; 896 897 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort); 898 WARN_ON(ret); 899 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert); 900 WARN_ON(ret); 901 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue); 902 WARN_ON(ret); 903 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue); 904 WARN_ON(ret); 905 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete); 906 WARN_ON(ret); 907 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce); 908 WARN_ON(ret); 909 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete); 910 WARN_ON(ret); 911 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); 912 WARN_ON(ret); 913 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); 914 WARN_ON(ret); 915 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue); 916 WARN_ON(ret); 917 ret = register_trace_block_getrq(blk_add_trace_getrq); 918 WARN_ON(ret); 919 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq); 920 WARN_ON(ret); 921 ret = register_trace_block_plug(blk_add_trace_plug); 922 WARN_ON(ret); 923 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer); 924 WARN_ON(ret); 925 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io); 926 WARN_ON(ret); 927 ret = register_trace_block_split(blk_add_trace_split); 928 WARN_ON(ret); 929 ret = register_trace_block_remap(blk_add_trace_remap); 930 WARN_ON(ret); 931 } 932 933 static void blk_unregister_tracepoints(void) 934 { 935 unregister_trace_block_remap(blk_add_trace_remap); 936 unregister_trace_block_split(blk_add_trace_split); 937 unregister_trace_block_unplug_io(blk_add_trace_unplug_io); 938 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer); 939 unregister_trace_block_plug(blk_add_trace_plug); 940 unregister_trace_block_sleeprq(blk_add_trace_sleeprq); 941 unregister_trace_block_getrq(blk_add_trace_getrq); 942 unregister_trace_block_bio_queue(blk_add_trace_bio_queue); 943 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); 944 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); 945 unregister_trace_block_bio_complete(blk_add_trace_bio_complete); 946 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce); 947 unregister_trace_block_rq_complete(blk_add_trace_rq_complete); 948 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue); 949 unregister_trace_block_rq_issue(blk_add_trace_rq_issue); 950 unregister_trace_block_rq_insert(blk_add_trace_rq_insert); 951 unregister_trace_block_rq_abort(blk_add_trace_rq_abort); 952 953 tracepoint_synchronize_unregister(); 954 } 955 956 /* 957 * struct blk_io_tracer formatting routines 958 */ 959 960 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 961 { 962 int i = 0; 963 int tc = t->action >> BLK_TC_SHIFT; 964 965 if (t->action == BLK_TN_MESSAGE) { 966 rwbs[i++] = 'N'; 967 goto out; 968 } 969 970 if (tc & BLK_TC_DISCARD) 971 rwbs[i++] = 'D'; 972 else if (tc & BLK_TC_WRITE) 973 rwbs[i++] = 'W'; 974 else if (t->bytes) 975 rwbs[i++] = 'R'; 976 else 977 rwbs[i++] = 'N'; 978 979 if (tc & BLK_TC_AHEAD) 980 rwbs[i++] = 'A'; 981 if (tc & BLK_TC_BARRIER) 982 rwbs[i++] = 'B'; 983 if (tc & BLK_TC_SYNC) 984 rwbs[i++] = 'S'; 985 if (tc & BLK_TC_META) 986 rwbs[i++] = 'M'; 987 out: 988 rwbs[i] = '\0'; 989 } 990 991 static inline 992 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 993 { 994 return (const struct blk_io_trace *)ent; 995 } 996 997 static inline const void *pdu_start(const struct trace_entry *ent) 998 { 999 return te_blk_io_trace(ent) + 1; 1000 } 1001 1002 static inline u32 t_action(const struct trace_entry *ent) 1003 { 1004 return te_blk_io_trace(ent)->action; 1005 } 1006 1007 static inline u32 t_bytes(const struct trace_entry *ent) 1008 { 1009 return te_blk_io_trace(ent)->bytes; 1010 } 1011 1012 static inline u32 t_sec(const struct trace_entry *ent) 1013 { 1014 return te_blk_io_trace(ent)->bytes >> 9; 1015 } 1016 1017 static inline unsigned long long t_sector(const struct trace_entry *ent) 1018 { 1019 return te_blk_io_trace(ent)->sector; 1020 } 1021 1022 static inline __u16 t_error(const struct trace_entry *ent) 1023 { 1024 return te_blk_io_trace(ent)->error; 1025 } 1026 1027 static __u64 get_pdu_int(const struct trace_entry *ent) 1028 { 1029 const __u64 *val = pdu_start(ent); 1030 return be64_to_cpu(*val); 1031 } 1032 1033 static void get_pdu_remap(const struct trace_entry *ent, 1034 struct blk_io_trace_remap *r) 1035 { 1036 const struct blk_io_trace_remap *__r = pdu_start(ent); 1037 __u64 sector_from = __r->sector_from; 1038 1039 r->device_from = be32_to_cpu(__r->device_from); 1040 r->device_to = be32_to_cpu(__r->device_to); 1041 r->sector_from = be64_to_cpu(sector_from); 1042 } 1043 1044 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1045 1046 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1047 { 1048 char rwbs[6]; 1049 unsigned long long ts = iter->ts; 1050 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1051 unsigned secs = (unsigned long)ts; 1052 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1053 1054 fill_rwbs(rwbs, t); 1055 1056 return trace_seq_printf(&iter->seq, 1057 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1058 MAJOR(t->device), MINOR(t->device), iter->cpu, 1059 secs, nsec_rem, iter->ent->pid, act, rwbs); 1060 } 1061 1062 static int blk_log_action(struct trace_iterator *iter, const char *act) 1063 { 1064 char rwbs[6]; 1065 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1066 1067 fill_rwbs(rwbs, t); 1068 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1069 MAJOR(t->device), MINOR(t->device), act, rwbs); 1070 } 1071 1072 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1073 { 1074 const unsigned char *pdu_buf; 1075 int pdu_len; 1076 int i, end, ret; 1077 1078 pdu_buf = pdu_start(ent); 1079 pdu_len = te_blk_io_trace(ent)->pdu_len; 1080 1081 if (!pdu_len) 1082 return 1; 1083 1084 /* find the last zero that needs to be printed */ 1085 for (end = pdu_len - 1; end >= 0; end--) 1086 if (pdu_buf[end]) 1087 break; 1088 end++; 1089 1090 if (!trace_seq_putc(s, '(')) 1091 return 0; 1092 1093 for (i = 0; i < pdu_len; i++) { 1094 1095 ret = trace_seq_printf(s, "%s%02x", 1096 i == 0 ? "" : " ", pdu_buf[i]); 1097 if (!ret) 1098 return ret; 1099 1100 /* 1101 * stop when the rest is just zeroes and indicate so 1102 * with a ".." appended 1103 */ 1104 if (i == end && end != pdu_len - 1) 1105 return trace_seq_puts(s, " ..) "); 1106 } 1107 1108 return trace_seq_puts(s, ") "); 1109 } 1110 1111 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1112 { 1113 char cmd[TASK_COMM_LEN]; 1114 1115 trace_find_cmdline(ent->pid, cmd); 1116 1117 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1118 int ret; 1119 1120 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1121 if (!ret) 1122 return 0; 1123 ret = blk_log_dump_pdu(s, ent); 1124 if (!ret) 1125 return 0; 1126 return trace_seq_printf(s, "[%s]\n", cmd); 1127 } else { 1128 if (t_sec(ent)) 1129 return trace_seq_printf(s, "%llu + %u [%s]\n", 1130 t_sector(ent), t_sec(ent), cmd); 1131 return trace_seq_printf(s, "[%s]\n", cmd); 1132 } 1133 } 1134 1135 static int blk_log_with_error(struct trace_seq *s, 1136 const struct trace_entry *ent) 1137 { 1138 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1139 int ret; 1140 1141 ret = blk_log_dump_pdu(s, ent); 1142 if (ret) 1143 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1144 return 0; 1145 } else { 1146 if (t_sec(ent)) 1147 return trace_seq_printf(s, "%llu + %u [%d]\n", 1148 t_sector(ent), 1149 t_sec(ent), t_error(ent)); 1150 return trace_seq_printf(s, "%llu [%d]\n", 1151 t_sector(ent), t_error(ent)); 1152 } 1153 } 1154 1155 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1156 { 1157 struct blk_io_trace_remap r = { .device_from = 0, }; 1158 1159 get_pdu_remap(ent, &r); 1160 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1161 t_sector(ent), t_sec(ent), 1162 MAJOR(r.device_from), MINOR(r.device_from), 1163 (unsigned long long)r.sector_from); 1164 } 1165 1166 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1167 { 1168 char cmd[TASK_COMM_LEN]; 1169 1170 trace_find_cmdline(ent->pid, cmd); 1171 1172 return trace_seq_printf(s, "[%s]\n", cmd); 1173 } 1174 1175 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1176 { 1177 char cmd[TASK_COMM_LEN]; 1178 1179 trace_find_cmdline(ent->pid, cmd); 1180 1181 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1182 } 1183 1184 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1185 { 1186 char cmd[TASK_COMM_LEN]; 1187 1188 trace_find_cmdline(ent->pid, cmd); 1189 1190 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1191 get_pdu_int(ent), cmd); 1192 } 1193 1194 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1195 { 1196 int ret; 1197 const struct blk_io_trace *t = te_blk_io_trace(ent); 1198 1199 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1200 if (ret) 1201 return trace_seq_putc(s, '\n'); 1202 return ret; 1203 } 1204 1205 /* 1206 * struct tracer operations 1207 */ 1208 1209 static void blk_tracer_print_header(struct seq_file *m) 1210 { 1211 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1212 return; 1213 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1214 "# | | | | | |\n"); 1215 } 1216 1217 static void blk_tracer_start(struct trace_array *tr) 1218 { 1219 blk_tracer_enabled = true; 1220 } 1221 1222 static int blk_tracer_init(struct trace_array *tr) 1223 { 1224 blk_tr = tr; 1225 blk_tracer_start(tr); 1226 return 0; 1227 } 1228 1229 static void blk_tracer_stop(struct trace_array *tr) 1230 { 1231 blk_tracer_enabled = false; 1232 } 1233 1234 static void blk_tracer_reset(struct trace_array *tr) 1235 { 1236 blk_tracer_stop(tr); 1237 } 1238 1239 static const struct { 1240 const char *act[2]; 1241 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1242 } what2act[] = { 1243 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1244 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1245 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1246 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1247 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1248 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1249 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1250 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1251 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1252 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1253 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1254 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1255 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1256 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1257 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1258 }; 1259 1260 static enum print_line_t print_one_line(struct trace_iterator *iter, 1261 bool classic) 1262 { 1263 struct trace_seq *s = &iter->seq; 1264 const struct blk_io_trace *t; 1265 u16 what; 1266 int ret; 1267 bool long_act; 1268 blk_log_action_t *log_action; 1269 1270 t = te_blk_io_trace(iter->ent); 1271 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1272 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1273 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1274 1275 if (t->action == BLK_TN_MESSAGE) { 1276 ret = log_action(iter, long_act ? "message" : "m"); 1277 if (ret) 1278 ret = blk_log_msg(s, iter->ent); 1279 goto out; 1280 } 1281 1282 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1283 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1284 else { 1285 ret = log_action(iter, what2act[what].act[long_act]); 1286 if (ret) 1287 ret = what2act[what].print(s, iter->ent); 1288 } 1289 out: 1290 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1291 } 1292 1293 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1294 int flags) 1295 { 1296 return print_one_line(iter, false); 1297 } 1298 1299 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1300 { 1301 struct trace_seq *s = &iter->seq; 1302 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1303 const int offset = offsetof(struct blk_io_trace, sector); 1304 struct blk_io_trace old = { 1305 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1306 .time = iter->ts, 1307 }; 1308 1309 if (!trace_seq_putmem(s, &old, offset)) 1310 return 0; 1311 return trace_seq_putmem(s, &t->sector, 1312 sizeof(old) - offset + t->pdu_len); 1313 } 1314 1315 static enum print_line_t 1316 blk_trace_event_print_binary(struct trace_iterator *iter, int flags) 1317 { 1318 return blk_trace_synthesize_old_trace(iter) ? 1319 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1320 } 1321 1322 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1323 { 1324 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1325 return TRACE_TYPE_UNHANDLED; 1326 1327 return print_one_line(iter, true); 1328 } 1329 1330 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1331 { 1332 /* don't output context-info for blk_classic output */ 1333 if (bit == TRACE_BLK_OPT_CLASSIC) { 1334 if (set) 1335 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1336 else 1337 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1338 } 1339 return 0; 1340 } 1341 1342 static struct tracer blk_tracer __read_mostly = { 1343 .name = "blk", 1344 .init = blk_tracer_init, 1345 .reset = blk_tracer_reset, 1346 .start = blk_tracer_start, 1347 .stop = blk_tracer_stop, 1348 .print_header = blk_tracer_print_header, 1349 .print_line = blk_tracer_print_line, 1350 .flags = &blk_tracer_flags, 1351 .set_flag = blk_tracer_set_flag, 1352 }; 1353 1354 static struct trace_event trace_blk_event = { 1355 .type = TRACE_BLK, 1356 .trace = blk_trace_event_print, 1357 .binary = blk_trace_event_print_binary, 1358 }; 1359 1360 static int __init init_blk_tracer(void) 1361 { 1362 if (!register_ftrace_event(&trace_blk_event)) { 1363 pr_warning("Warning: could not register block events\n"); 1364 return 1; 1365 } 1366 1367 if (register_tracer(&blk_tracer) != 0) { 1368 pr_warning("Warning: could not register the block tracer\n"); 1369 unregister_ftrace_event(&trace_blk_event); 1370 return 1; 1371 } 1372 1373 return 0; 1374 } 1375 1376 device_initcall(init_blk_tracer); 1377 1378 static int blk_trace_remove_queue(struct request_queue *q) 1379 { 1380 struct blk_trace *bt; 1381 1382 bt = xchg(&q->blk_trace, NULL); 1383 if (bt == NULL) 1384 return -EINVAL; 1385 1386 if (atomic_dec_and_test(&blk_probes_ref)) 1387 blk_unregister_tracepoints(); 1388 1389 blk_trace_free(bt); 1390 return 0; 1391 } 1392 1393 /* 1394 * Setup everything required to start tracing 1395 */ 1396 static int blk_trace_setup_queue(struct request_queue *q, 1397 struct block_device *bdev) 1398 { 1399 struct blk_trace *old_bt, *bt = NULL; 1400 int ret = -ENOMEM; 1401 1402 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1403 if (!bt) 1404 return -ENOMEM; 1405 1406 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1407 if (!bt->msg_data) 1408 goto free_bt; 1409 1410 bt->dev = bdev->bd_dev; 1411 bt->act_mask = (u16)-1; 1412 1413 blk_trace_setup_lba(bt, bdev); 1414 1415 old_bt = xchg(&q->blk_trace, bt); 1416 if (old_bt != NULL) { 1417 (void)xchg(&q->blk_trace, old_bt); 1418 ret = -EBUSY; 1419 goto free_bt; 1420 } 1421 1422 if (atomic_inc_return(&blk_probes_ref) == 1) 1423 blk_register_tracepoints(); 1424 return 0; 1425 1426 free_bt: 1427 blk_trace_free(bt); 1428 return ret; 1429 } 1430 1431 /* 1432 * sysfs interface to enable and configure tracing 1433 */ 1434 1435 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1436 struct device_attribute *attr, 1437 char *buf); 1438 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1439 struct device_attribute *attr, 1440 const char *buf, size_t count); 1441 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1442 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1443 sysfs_blk_trace_attr_show, \ 1444 sysfs_blk_trace_attr_store) 1445 1446 static BLK_TRACE_DEVICE_ATTR(enable); 1447 static BLK_TRACE_DEVICE_ATTR(act_mask); 1448 static BLK_TRACE_DEVICE_ATTR(pid); 1449 static BLK_TRACE_DEVICE_ATTR(start_lba); 1450 static BLK_TRACE_DEVICE_ATTR(end_lba); 1451 1452 static struct attribute *blk_trace_attrs[] = { 1453 &dev_attr_enable.attr, 1454 &dev_attr_act_mask.attr, 1455 &dev_attr_pid.attr, 1456 &dev_attr_start_lba.attr, 1457 &dev_attr_end_lba.attr, 1458 NULL 1459 }; 1460 1461 struct attribute_group blk_trace_attr_group = { 1462 .name = "trace", 1463 .attrs = blk_trace_attrs, 1464 }; 1465 1466 static const struct { 1467 int mask; 1468 const char *str; 1469 } mask_maps[] = { 1470 { BLK_TC_READ, "read" }, 1471 { BLK_TC_WRITE, "write" }, 1472 { BLK_TC_BARRIER, "barrier" }, 1473 { BLK_TC_SYNC, "sync" }, 1474 { BLK_TC_QUEUE, "queue" }, 1475 { BLK_TC_REQUEUE, "requeue" }, 1476 { BLK_TC_ISSUE, "issue" }, 1477 { BLK_TC_COMPLETE, "complete" }, 1478 { BLK_TC_FS, "fs" }, 1479 { BLK_TC_PC, "pc" }, 1480 { BLK_TC_AHEAD, "ahead" }, 1481 { BLK_TC_META, "meta" }, 1482 { BLK_TC_DISCARD, "discard" }, 1483 { BLK_TC_DRV_DATA, "drv_data" }, 1484 }; 1485 1486 static int blk_trace_str2mask(const char *str) 1487 { 1488 int i; 1489 int mask = 0; 1490 char *buf, *s, *token; 1491 1492 buf = kstrdup(str, GFP_KERNEL); 1493 if (buf == NULL) 1494 return -ENOMEM; 1495 s = strstrip(buf); 1496 1497 while (1) { 1498 token = strsep(&s, ","); 1499 if (token == NULL) 1500 break; 1501 1502 if (*token == '\0') 1503 continue; 1504 1505 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1506 if (strcasecmp(token, mask_maps[i].str) == 0) { 1507 mask |= mask_maps[i].mask; 1508 break; 1509 } 1510 } 1511 if (i == ARRAY_SIZE(mask_maps)) { 1512 mask = -EINVAL; 1513 break; 1514 } 1515 } 1516 kfree(buf); 1517 1518 return mask; 1519 } 1520 1521 static ssize_t blk_trace_mask2str(char *buf, int mask) 1522 { 1523 int i; 1524 char *p = buf; 1525 1526 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1527 if (mask & mask_maps[i].mask) { 1528 p += sprintf(p, "%s%s", 1529 (p == buf) ? "" : ",", mask_maps[i].str); 1530 } 1531 } 1532 *p++ = '\n'; 1533 1534 return p - buf; 1535 } 1536 1537 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1538 { 1539 if (bdev->bd_disk == NULL) 1540 return NULL; 1541 1542 return bdev_get_queue(bdev); 1543 } 1544 1545 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1546 struct device_attribute *attr, 1547 char *buf) 1548 { 1549 struct hd_struct *p = dev_to_part(dev); 1550 struct request_queue *q; 1551 struct block_device *bdev; 1552 ssize_t ret = -ENXIO; 1553 1554 lock_kernel(); 1555 bdev = bdget(part_devt(p)); 1556 if (bdev == NULL) 1557 goto out_unlock_kernel; 1558 1559 q = blk_trace_get_queue(bdev); 1560 if (q == NULL) 1561 goto out_bdput; 1562 1563 mutex_lock(&bdev->bd_mutex); 1564 1565 if (attr == &dev_attr_enable) { 1566 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1567 goto out_unlock_bdev; 1568 } 1569 1570 if (q->blk_trace == NULL) 1571 ret = sprintf(buf, "disabled\n"); 1572 else if (attr == &dev_attr_act_mask) 1573 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1574 else if (attr == &dev_attr_pid) 1575 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1576 else if (attr == &dev_attr_start_lba) 1577 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1578 else if (attr == &dev_attr_end_lba) 1579 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1580 1581 out_unlock_bdev: 1582 mutex_unlock(&bdev->bd_mutex); 1583 out_bdput: 1584 bdput(bdev); 1585 out_unlock_kernel: 1586 unlock_kernel(); 1587 return ret; 1588 } 1589 1590 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1591 struct device_attribute *attr, 1592 const char *buf, size_t count) 1593 { 1594 struct block_device *bdev; 1595 struct request_queue *q; 1596 struct hd_struct *p; 1597 u64 value; 1598 ssize_t ret = -EINVAL; 1599 1600 if (count == 0) 1601 goto out; 1602 1603 if (attr == &dev_attr_act_mask) { 1604 if (sscanf(buf, "%llx", &value) != 1) { 1605 /* Assume it is a list of trace category names */ 1606 ret = blk_trace_str2mask(buf); 1607 if (ret < 0) 1608 goto out; 1609 value = ret; 1610 } 1611 } else if (sscanf(buf, "%llu", &value) != 1) 1612 goto out; 1613 1614 ret = -ENXIO; 1615 1616 lock_kernel(); 1617 p = dev_to_part(dev); 1618 bdev = bdget(part_devt(p)); 1619 if (bdev == NULL) 1620 goto out_unlock_kernel; 1621 1622 q = blk_trace_get_queue(bdev); 1623 if (q == NULL) 1624 goto out_bdput; 1625 1626 mutex_lock(&bdev->bd_mutex); 1627 1628 if (attr == &dev_attr_enable) { 1629 if (value) 1630 ret = blk_trace_setup_queue(q, bdev); 1631 else 1632 ret = blk_trace_remove_queue(q); 1633 goto out_unlock_bdev; 1634 } 1635 1636 ret = 0; 1637 if (q->blk_trace == NULL) 1638 ret = blk_trace_setup_queue(q, bdev); 1639 1640 if (ret == 0) { 1641 if (attr == &dev_attr_act_mask) 1642 q->blk_trace->act_mask = value; 1643 else if (attr == &dev_attr_pid) 1644 q->blk_trace->pid = value; 1645 else if (attr == &dev_attr_start_lba) 1646 q->blk_trace->start_lba = value; 1647 else if (attr == &dev_attr_end_lba) 1648 q->blk_trace->end_lba = value; 1649 } 1650 1651 out_unlock_bdev: 1652 mutex_unlock(&bdev->bd_mutex); 1653 out_bdput: 1654 bdput(bdev); 1655 out_unlock_kernel: 1656 unlock_kernel(); 1657 out: 1658 return ret ? ret : count; 1659 } 1660 1661 int blk_trace_init_sysfs(struct device *dev) 1662 { 1663 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1664 } 1665 1666 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1667 1668 #ifdef CONFIG_EVENT_TRACING 1669 1670 void blk_dump_cmd(char *buf, struct request *rq) 1671 { 1672 int i, end; 1673 int len = rq->cmd_len; 1674 unsigned char *cmd = rq->cmd; 1675 1676 if (!blk_pc_request(rq)) { 1677 buf[0] = '\0'; 1678 return; 1679 } 1680 1681 for (end = len - 1; end >= 0; end--) 1682 if (cmd[end]) 1683 break; 1684 end++; 1685 1686 for (i = 0; i < len; i++) { 1687 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1688 if (i == end && end != len - 1) { 1689 sprintf(buf, " .."); 1690 break; 1691 } 1692 } 1693 } 1694 1695 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1696 { 1697 int i = 0; 1698 1699 if (rw & WRITE) 1700 rwbs[i++] = 'W'; 1701 else if (rw & 1 << BIO_RW_DISCARD) 1702 rwbs[i++] = 'D'; 1703 else if (bytes) 1704 rwbs[i++] = 'R'; 1705 else 1706 rwbs[i++] = 'N'; 1707 1708 if (rw & 1 << BIO_RW_AHEAD) 1709 rwbs[i++] = 'A'; 1710 if (rw & 1 << BIO_RW_BARRIER) 1711 rwbs[i++] = 'B'; 1712 if (rw & 1 << BIO_RW_SYNCIO) 1713 rwbs[i++] = 'S'; 1714 if (rw & 1 << BIO_RW_META) 1715 rwbs[i++] = 'M'; 1716 1717 rwbs[i] = '\0'; 1718 } 1719 1720 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1721 { 1722 int rw = rq->cmd_flags & 0x03; 1723 int bytes; 1724 1725 if (blk_discard_rq(rq)) 1726 rw |= (1 << BIO_RW_DISCARD); 1727 1728 bytes = blk_rq_bytes(rq); 1729 1730 blk_fill_rwbs(rwbs, rw, bytes); 1731 } 1732 1733 #endif /* CONFIG_EVENT_TRACING */ 1734 1735